The present invention relates in general to portable bed stiffeners of the type designed to be inserted between the mattress and box springs of a bed to impart additional stiffness to the mattress, particularly for use by persons with back problems requiring firmer bed mattress support. More particularly the present invention relates to portable bed mattress stiffeners of the above-identified type arranged in the form of a plurality of slats capable of being rolled into a compact roll for convenience of transportation.
Heretofore, it has been long recognized that persons suffering from back or spinal problems need firmer mattress support in beds used by such persons to minimize aching or soreness in the back or spinal region as may occur following sleeping on a bed mattress which is too soft. One of the most common aids to impart additional stiffness to a bed mattress to be used by such persons is to insert what is usually referred to as a "bed board" between the mattress and box springs, which spans a major portion of the width and length of the mattress. This is customarily simply a plywood, pressed wood, or other similar wood panel usually about one quarter to three eighths inch thick in the form of a rectangle about three feet by four feet in size.
Since such bed boards would obviously be too large and uunwieldly to be readily transportable during traveling by persons desiring to have a bed board or similar mattress with them, it has been previously proposed to subdivide such bed boards into smaller sections which are foldable to occupy a smaller space and be more readily transportable. Rickert U.S. Pat. No. 3,125,678 and Krueger U.S. Pat. No. 4,649,583 are examples of posture boards or bed boards which are foldable, and are designed to be interposed between the mattress and box springs of a bed mattress and spring arrangement. However such foldable posture boards or bed boards are still relatively large and inconvenient to transport.
A portable arrangement of cords and slats is disclosed in Smith U.S. Pat. No. 2,551,927, to facilitate transportation in a folded, compact form, and which is unfolded and placed on a mattress of a bed to provide support for osteopathic treatment, although in this arrangement the slats are designed to extend lengthwise of the bed rather than crosswise, and apparently are designed to lie on top of the mattress rather than between the mattress and the box springs.
The Eriksson U.S. Pat. No. 3,280,515 discloses a supplemental support for a bed mattress adapted to be placed beneath the mattress, in which a pair of flexible sheets are secured together to form a plurality of pockets spanning one dimension of the sheets, to receive resilient rods providing a selected amount of stiffness and imparting additional stiffness to the mattress along the longitudinal direction of the rods by adjustment of the springiness of the rods. Localized stiffness at different locations can be obtained. Similarly, U.S. Pat. No. 2,728,089 to Hynes discloses a mattress stiffener having a plurality of tubular members joined by flexible means in parallel spaced relation to one another, which also provides stiffness in the longitudinal direction of the tubular members. Flexible joined rigid slats arranged parallel to each other are also disclosed as a back rest for vehicle riding, in the Boland U.S. Pat. No. 2,745,473. However, in each of the Erickson, Heinz and Boland patents, the stiffness and resistance to distortion occur only along the longitudinal direction of the rods, tubular members or slats, and there is no resistance to distortion of the mattress support in the direction perpendicular to the longitudinal axis of the rods, tubular members or slats since they are interconnected by flexible means.
An object of the present invention is the provision of a portable mattress stiffener or supplemental support for bed mattresses adapted to be placed between the mattress and underlying box springs, which is formed of a plurality of elongated slat members of relatively thin, generally rectangular cross-sectional configuration having interfitting hinge formations on adjacent confronting side walls thereof and having abutment surfaces coactive to permit rolling up of the plural slat mattress stiffener assembly when rolled into a spiral form in one direction, and wherein the hinge and associated abutment surfaces coact when the slat assembly is unrolled to resist deformation of the hinged together slats from a predetermined substantially planar or planiform arrangement.
Other objects, advantages and capabilities of the present invention will become apparent from the detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.